On Tue, Sep 12, 2017 at 04:07:01PM +0800, Huang, Ying wrote: < snip > > >> > My concern is users have been disabled swap readahead by page-cluster would > >> > be regressed. Please take care of them. > >> > >> How about disable VMA based swap readahead if zram used as swap? Like > >> we have done for hard disk? > > > > It could be with SWP_SYNCHRONOUS_IO flag which indicates super-fast, > > no seek cost swap devices if this patchset is merged so VM automatically > > disables readahead. It is in my TODO but it's orthogonal work. > > > > The problem I raised is "Why shouldn't we obey user's decision?", > > not zram sepcific issue. > > > > A user has used SSD as swap devices decided to disable swap readahead > > by some reason(e.g., small memory system). Anyway, it has worked > > via page-cluster for a several years but with vma-based swap devices, > > it doesn't work any more. > > Can they add one more line to their configuration scripts? > > echo 0 > /sys/kernel/mm/swap/vma_ra_max_order We call it as "regression", don't we? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
